Motor.



B. H. HERNDON.

MOTOR. APPLICATION FILED. NOVA, 1907.

Patented De0.28,1909.

UNITED STATES PATENT OFFICE.

EMMETT H. HERNDON, OF SANFORD, FLORIDA.

MOTOR.

Patented Dec. 28, 1909.

Original application filed July 10, 1907, Serial No. 383,056. Dividedand this application filed November 4,

To all whom it may concern:

Be it known that I, EMMETT H. HERNDoN, a citizen of the United States,residing at Sanford, in the county of Orange and State of Florida, haveinvented a new and useful Motor, of which the following is aspecification.

This invention relates to a novel form of motor or engine of the typewherein the ignition of' an explosive mixture creates a pressure topropel the moving parts of the engine.

An object of the invention is to provide an engine in which provision ismade for ready conversion into either two cycle or four cycle type.

WVith this and other objects in view, as will more fully hereinafterappear, the invention consists in certain novel features of constructionand arrangement ofparts, hereinafter fully described, illustrated in theaccompanying drawings, and particularly pointed out in the appendedclaims, it being understood that various changes in the form,proportions, size and minor details of the structure may be made withoutdeparting from the spiritor sacrificing any of the advantages of theinvention.

In the accompanying drawings :Figure 1 is a side elevation of a motorprovided with an internal combustion engine constructed in accordancewith the invention. Fig. 2 is a transverse view of the motor on the line22 of Fig. 1. Fig. 3 is a diagram showing the operation of the main andauxiliary pistons.

Similar numerals of reference are employed to indicate correspondingparts throughout the several figures of the drawlngs.

The present application is a division of an application for LettersPatent on which Letters Patent No. 896,4l48 were granted to me on August18, 1908, for a motor.

The motor which forms the subject of the foregoing patent is one inwhich three pairs of alining cylinders are arranged at equidistantintervals around a main shaft. The two pistons belonging to each pair ofcylinders are rigidly connected and each pair carries a pin orprojection which enters a helical return groove formed inthe shaft orSerial No. 400,567.

a drum that is rigidly secured to the same. As the pistons arereciprocated, the pins or projections traverse this helical groove andcause the shaft to rotate. The shaft controls the timing devices, andfurther operates to return the scavenging pistons of the cylinders ashereinafter described.

The general frame of the engine includes boxes 10, rigidly securedtogether by a tu bular shell 11, and each box is provided withsemi-circular depressions 16, for the reception of the three sets ofcylinders 17, the cylinders being confined in place by straps 18. Theboxes 10 are hollow and constitute exhaust chambers which are in freecom munication with the cylinders through ports 20, the latter beingarranged to open when the piston reaches the limit of the workingstroke, and these boxes communicate with a muffler 21 having a dischargepipe 22 through which the products of combustion from all of thecylinders finally escape. Se cured rigidly to the shaft at a pointbetween the two boxes is a drum 27 that is provided with a returnhelical groove 28 of such pitch that there will not be undue frictionbetween the walls of the groove and the piston actuated members whichenter such groove.

The cylinders are arranged in pairs, those constituting each pair beingarranged with their axes in alinement and within each pair of cylindersfits a double ended piston 29. Projecting from the central portion ofeach piston is a stud 30 carrying two anti-friction rollers 31 and 32,all of the rollers 32 entering the helical groove of the drum 27, whileall of the rollers 31 are arranged for contactwith the walls of theslots 33 that are formed in the cylindrical shell 11. These slots 33extend longitudinally of the shell and are parallel with the axes of theshaft and cylinders, so that they serve to maintain the studs 30 inproper position and prevent any turning of the pistons on their axes, sothat the pistons proper are not subjected to any torsional strain fromthe engagement of the rollers 32 with the walls of the helical slot 28.Each of the pistons 29 is preferably in the form of a hollow cylinderclosed at both ends and preferably ofuniform diameter throughout itsentire length, although it may be in the form of a pair of piston headsconnected by a stem of less diameter than the heads.

Each of the cylinders is of precisely the same construction as theothers, the explo sion chamber having a cap or cover 38 from whichextends a tube 39, the axis of which is coincident with that of thecylinder. Through this tube passes a rod 40 carrying at its inner end anauxiliary piston 41 111 which are formed one or more transverse ports42.

These ports are provided with valves 43 that.

are normally held in closed position by springs 44 coiled around thevalve stems and bearing at one end against the piston and at theopposite end against adjustable nuts carried by the stems. The outer endof the rod 40 carries a hook 45 to which the outer end of a tensionspring 46 may be attached, the inner end of the spring being connectedto an eye on the head of the explosion chamber, the hook projectingthrough an elongated slot 47 formed in the wall of the tube 39, and saidspring tending at all times to force the auxiliary piston 41 away fromthe head of the explosion chamber.

Projecting from the stem 40 is an antifriction roller 48 that is mountedon a stem 49 passing through a slot 50 formed in tube 39. This roller isarranged to be engaged by a cam 51 011 the shaft, the shaft beingprovided with two cams one for each set of op era ting cylinders at eachend of the motor.

At the explosion chamber head is an inlet 53 leading from the carbureteror other source of supply and through which the explosive mixture isadmitted to the cylinder. Arranged slightly in advance of each auxiliarypiston is a sparker 54 of any ordinary construction, provision beingmade for controlling the igniting circuits in order to advance or retardthe spark, as desired.

In the operation of the motor as a two cycle engine, reference is had tothe cylinder shown in Fig. 1, wherein the piston 29 is traveling towardthe right and has nearly reached the end of the working stroke, it beingobserved that the escape port 20 of the left hand cylinder is nearlyfull open. During this working stroke the pressure of gases within thecylinder has kept the auxiliary piston stationary, although the roller48 of the latter is at this time out of engagement with its operatingcam 51. As soon, however, as the port 20 opens to such an extent as topermit the partial discharge of the products of combustion the pressurein the cylinder will reduce to a point below the stress exerted by thespring 46, which at this time has been placed under tension. Vhen thepressure reduces to a point below the strength of the spring, the latterin retracting will force the auxiliary piston inward toward the exhaustport, thereby forcing out the remainder of the exploded charge, and,

at the same time, creating a partial vacuum at the explosion chamber endof the cylinder, thereby causing an inflow of an explosive charge, andduring this movement the valves 43 will remain closed in order toprevent the admixture of the fresh charge with the ex ploded gases.

As the anti-friction roller of the piston makes the turn in the helicalgroove 28, the roller 48 of the auxiliary piston will be engaged by thecam 51 and the auxiliary piston will be moved outward by the cam inadvance of the piston 29, as will be evident 011 reference to thediagram, Fig. 3, where the inclination of the cam is shown to be muchquicker than the inclination of the groove, so that the auxiliary pistonwill arrive at the end of its out stroke or the stroke toward theexplosion chamber head long before the main piston completes its strokein the same direction. During this out stroke of the auxiliary pistonthe valves 43 open and the fresh charge passes to the space between thetwo pistons and is compressed therebetween as the main piston completesits stroke, and at the end of this stroke the fresh charge of compressedexplosive mixture is ignited by the spark plug and another workingstroke is effected.

When the engine is to be operated on the four cycle principle, thespring 46 is detached from the hook 45 and the rod 40 is locked to thetube 39 so as to prevent movement of the auxiliary piston 42, the rod 40being provided with an opening 7 9 into which a suitable pin may beinserted for this purpose. The device will then operate as an ordinaryfour cycle engine with the exception that the exhaust port will be underthe control of the main piston and will be opened by the piston when thelatter reaches the limit of the working stroke.

I claim 1. In an internal combustion engine, a cylinder having an inletport at the explosion chamber end and a piston controlled exhaust portat the opposite end, a main piston within the cylinder, and anotherpiston in the cylinder at the explosion chamber end thereof and providedwith a valved port opening toward the main piston,.1neans for moving thesecond named piston to expel the burned gases and to draw in a freshcharge at the completion of the working stroke, and means for lockingthe second named piston in the retracted position to convert the engineinto a four cycle engine.

2. In an internal combustion engine, a cylinder having an intake port atthe explosion chamber end and a piston controlled exhaust port near theopposite end, a main piston working in said cylinder, an auxiliarypiston having valved ports extending therethrough, an operating rodextending from the auxiliary piston, a spring connected to the rod andtending to force the auxiliary In testimony that I claim the foregoingas piston in the direction of the exhaust port, my own I have heretoaffixed my signature means for moving the auxiliary piston in the l inthe presence of tWo Witnesses.

opposite direction, and means for locking EMMETT H. HERNDON. saidauxiliary piston from movement When Witnesses:

the engine is to operate as a four cycle en- F. T. FOSTER,

gine. B. F. WHITNER, Jr.

